ceilometermiddleware listener incorrect key check

[gordon chung]

i incorrectly used: "if message['payload']['measurements']:" to check for valid key (https://github.com/openstack/ceilometer/blob/master/ceilometer/objectstore/notifications.py#L72)

this is causing notification logs to be littered with errors:

2015-03-23 19:19:00.859 31517 ERROR oslo_messaging.notify.dispatcher [-] Exception during message handling
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher Traceback (most recent call last):
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/notify/dispatcher.py", line 91, in _dispatch_and_handle_error
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher executor_callback)
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/notify/dispatcher.py", line 134, in _dispatch
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher metadata)
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher File "/opt/stack/new/ceilometer/ceilometer/agent/plugin_base.py", line 159, in info
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher self.to_samples_and_publish(context.get_admin_context(), notification)
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher File "/opt/stack/new/ceilometer/ceilometer/agent/plugin_base.py", line 187, in to_samples_and_publish
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher p(list(self.process_notification(notification)))
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher File "/opt/stack/new/ceilometer/ceilometer/objectstore/notifications.py", line 72, in process_notification
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher if message['payload']['measurements']:
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher KeyError: 'measurements'
2015-03-23 19:19:00.859 31517 TRACE oslo_messaging.notify.dispatcher

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/166998

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/166998
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=2b6b724e4f6dc1de9d8b3fca705324458c03dd9b
Submitter: Jenkins
Branch: master

commit 2b6b724e4f6dc1de9d8b3fca705324458c03dd9b
Author: gordon chung <email address hidden>
Date: Mon Mar 23 16:26:49 2015 -0400

    fix incorrect key check in swift notifications

    ceilometermiddleware emits notifications that may or may not contain
    measurement values. the original key check logic i added is not
    correct so this fixes it.

    Change-Id: Ib18e29457673cf9f67125c3d453c98fec075f16b
    Closes-Bug: #1435533